Protective bonding serves what primary purpose in an electrical installation, and how is it implemented?

• A. To equalize the potential of exposed metalwork; implemented by bonding to the protective conductor network.
• B. To increase circuit impedance by adding parallel paths.
• C. To connect neutral to earth directly.
• D. To improve lighting efficiency by grounding only metal fixtures.

Answer: (A)

Protective bonding keeps exposed metal parts at the same electrical potential as the earth so that if a fault makes a metal surface live, the voltage difference to touch is minimized and fault current has a quick low-impedance path to earth. This is achieved by linking all exposed conductive parts to the protective conductor network (the PE system) that ties back to the main earthing point. That setup is what the statement describes: equalizing the potential of exposed metalwork by bonding it to the protective conductor network. The other ideas would not provide a low-impedance fault path, risk direct neutral-to-earth connections, or relate to efficiency rather than safety.